1. Field of the Invention
This invention relates to the paper making art and is more particularly concerned with a new and improved paper making machine dryer section drive.
2. Brief Description of the Prior Art
After the paper web has been dewatered in a paper making machine to the extent that it is self-supporting, the web is caused to travel through a dryer section having a plurality of rotatably mounted heated dryer drums or rolls arranged in cooperative upper and lower tiers and over which the paper web to be dried is adapted to travel in a sinuous path successively around the dryer rolls of the tiers. Respective dryer felts guide and hold the web onto the roll peripheral surfaces of each tier. Each dryer felt also functions to maintain substantial synchronism of the dryer rolls in the respective tier with which the felt is associated. Representative of this type of dryer section is the disclosure in U.S. Pat. No. 3,815,256.
In the modern day dryer sections, which may operate at lineal or machine direction speeds of about 3000 feet per minute, it has been customary to drive the entire dryer section by means of one large driving motor and then through a long train of gears at the backside of the machine, all of the dryer rolls, which may be as many as 15 in a typical dryer section, are driven in unison from the single motor. This requires a fairly massive and costly frame and gearbox arrangement, which interferes with symmetrical air flow from the paper machine basement, in contrast to the front side of the dryer section which is not encumbered with the gear box structure. Because of the large number of gears in the train, considerable operating noise is generated. Customarily, the gears are lubricated with oil and oil leakage can be a problem.